“This defense can be rolled out incrementally, requiring only software modification on at least one widely-used Bluetooth Low Energy chipset”
Phones and trackers broadcast roughly 500 Bluetooth beacons a minute. MAC randomization changes the name tag, but manufacturing flaws in each radio leave a physical fingerprint that never changes. UC San Diego showed the tracking attack in 2022 and now has a firmware fix running on a Texas Instruments CC2640. It still needs chipmakers to ship it, and nobody selling radios has much reason to.